NATURAL HISTORY OF AQUATIC INSECTS CH. 



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FIG. 67.^-Stratiomys chamaeleon. i, larva; 2, hrva floating at surface of water; 

 3, larva descending ; 4, pupa within larval skin (2, 3, and 4 are from Swammer- 

 dam, Biblia Natures) ; 5, head of larva, dorsal view, a a. marks the attachment 

 of the thoracic integument ; 6, head of larva, ventral view. The ventral wall is 

 incomplete behind, and the pharynx and gullet are exposed ; 7, piece of integu- 

 ment ; 8, do. in section, with conical, calcareous nails ; 9, a single calcareous 

 nail, surface view ; 10, spiracle, lying in centre of tail-coronet. 



